Enhanced Corrosion Protection of Mild Steel with Ferrocene-Fortified Graphite Epoxy Coatings

Ferrocene (FC) derivatives have long been explored as corrosion inhibitors for mild steel (MS) in aqueous environments; however, their incorporation into protective coatings remains largely unexplored. Here, we report the first-time employment of pristine FC as an anticorrosive additive within a graphite-epoxy coating (GEC) to significantly enhance the corrosion resistance of MS. FC was incorporated at varying loadings (0–16 wt %) into GEC using an acetone/chloroform (20:80; wt/wt) azeotrope as the processing medium. Its successful fortification was verified using spectroscopic and microscopic analyses, including LIBS, XRD, Raman, FTIR, and EDS. Electrochemical impedance spectroscopy demonstrated a maximum corrosion protection efficiency of 99.78% for 16 wt % FC-fortified GEC after 120 h of immersion in 3.5 wt % aqueous NaCl solution, consistent with Tafel polarization (99.07%). The coatings also exhibited a markedly reduced corrosion rate (0.26 μm/yr), stable wettability with 99.9% contact angle retention, and negligible weight loss (0.71%) under salt-spray exposure at 95% relative humidity for 10 days. These superior performances are attributed to a diffusion-controlled redox mechanism wherein FC confined within graphitic layers regulates charge transport and impedes electrolyte penetration. This study establishes pristine FC as a versatile additive for epoxy-based protective coatings, offering a cost-effective route to the corrosion protection of MS in aggressive environments.